The invention concerns an apparatus for electrostatic spray-enameling plastic parts in a spray booth using a conducting liquid spray-deposited on the parts surfaces prior to enameling.
Deposition of a conducting liquid on the surface of the plastic parts is required in electrostatic enameling because the plastic parts are insulators which as such do not allow electrostatic enameling. Accordingly the conducting liquid forms the required opposite pole permitting the apposition of the charged paint particles on the surface of the plastic parts.
The conducting liquid is a solution of polar conducting substances in highly volatile alcohols. Thus the conducting liquid consists of a solvent and a vehicle, the solvent of the solution uniformly distributing the vehicle during deposition.
In a known apparatus the objects to be enameled are made to pass with so-called hangers through a spray booth, for which they must be individually suspended into the conveyor hooks of the hangers before enameling and then be removed from these hooks after enameling.
However such a conveying system is inapplicable where long, bar-shaped sections are involved because these bar-shaped components would too strongly warp at their ends when suspended or because requiring laborious suspension at several places along their length. The latter eventuality in particular incurs the drawback that additional points of contact would be created which would be inaccessible to the enamel and therefore subsequent enameling would be required at those places.